MCQOPTIONS
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MCQOPTIONS
This section includes 509 Mcqs, each offering curated multiple-choice questions to sharpen your Machine Design knowledge and support exam preparation. Choose a topic below to get started.
| 301. |
In order to reverse the direction of rotation of a 3-phase induction motor |
| A. | Motor should eb replaced |
| B. | Power factor should be changed |
| C. | Supply voltage should be cut off in one phase |
| D. | Any two phases should be interchanged |
| E. | All the three phases should be interchanged |
| Answer» E. All the three phases should be interchanged | |
| 302. |
Gerber line for failure criteria is in the form of a |
| A. | parabola |
| B. | Increasing the diameter of threaded portion |
| C. | straight line with negative slope |
| D. | straight line with positive slope |
| E. | hyperbola |
| Answer» B. Increasing the diameter of threaded portion | |
| 303. |
If water in closed pipe freezes, the pipe will |
| A. | Rupture in a plane inclined at 45 degree to the longitudinal axis of the pipe |
| B. | Rupture along a line running longitudinally along the pipe |
| C. | Rupture along a plane perpendicular to the axis of pipe |
| D. | Rupture zig-zag along the length |
| E. | Rupture along weakest circumferential section |
| Answer» C. Rupture along a plane perpendicular to the axis of pipe | |
| 304. |
While designing a shaft pulley and key for a system |
| A. | Shaft is the weakest member |
| B. | Pulley is the weakest member |
| C. | Key is the weakest member |
| D. | All are designed for equal strength |
| E. | None of the above |
| Answer» D. All are designed for equal strength | |
| 305. |
In case of steels, as the percentage of carbon content increases |
| A. | Elongation increases |
| B. | Chrome steel |
| C. | Hardness decreases |
| D. | Tensile strength increases |
| E. | Weldability increases |
| Answer» E. Weldability increases | |
| 306. |
The approximate value of allowable stress for carbon steel under static loading (in kg/cm2) is |
| A. | 500-1000 |
| B. | 10000-15000 |
| C. | 4000-7500 |
| D. | 20000-25000 |
| E. | 15000-20000 |
| Answer» D. 20000-25000 | |
| 307. |
Bush bearings |
| A. | Phosphor bronze |
| B. | Aluminium bronze |
| C. | Mild steel |
| D. | White metal alloys |
| E. | None of the above |
| Answer» E. None of the above | |
| 308. |
A solderberg line for ductile material gives upper limit for |
| A. | Increasing the diameter of threaded portion |
| B. | alternating tensile stress |
| C. | alternating compressive stress |
| D. | any combination of mean and alternating stresses |
| E. | mean stress |
| Answer» E. mean stress | |
| 309. |
The basic hole is one which has |
| A. | Upper deviation as zero |
| B. | Lower deviation as zero |
| C. | Lower as well as upper deviation within narrow limits |
| D. | Lower as well as upper deviation are zero |
| E. | None of the above |
| Answer» C. Lower as well as upper deviation within narrow limits | |
| 310. |
At the first critical speed a shaft will |
| A. | Remain straight |
| B. | Bend to the simplest shape possible |
| C. | Bend to maximum permissible depth |
| D. | Bend to the convex form |
| E. | Vibrate producing audible sound |
| Answer» C. Bend to maximum permissible depth | |
| 311. |
Which of the following joint is used for pipes carrying water under low pressures? |
| A. | Socket joint |
| B. | Increasing the diameter of threaded portion |
| C. | Expansion joint |
| D. | Adhesive joint |
| E. | Welded joint |
| Answer» B. Increasing the diameter of threaded portion | |
| 312. |
For a bearing which of the following is maximum? |
| A. | Minimum life |
| B. | Average life |
| C. | Median life |
| D. | (A), (B) and (C) above are identical |
| E. | Increasing the diameter of threaded portion |
| Answer» D. (A), (B) and (C) above are identical | |
| 313. |
When properly made, a butt weld has the strength equal to |
| A. | Double the tensile strength of plates |
| B. | Half the tensile strength of plates |
| C. | Half the compressive strength of plates |
| D. | The strength of the welded plates |
| E. | Double the compressive strength of plates |
| Answer» E. Double the compressive strength of plates | |
| 314. |
In case of worm and worm-wheel the maximum efficiency is obtained when |
| A. | Worm is driver |
| B. | Worm wheel is driver |
| C. | Either of the worm or worm wheel is a driver |
| D. | Depends on other factors |
| E. | None of the above |
| Answer» D. Depends on other factors | |
| 315. |
Auto frettage is a |
| A. | extra cover provided on seamless pipes to increase their hoop stress |
| B. | a means of inducing favourable residual stresses in pressure vessels |
| C. | Increasing the diameter of threaded portion |
| D. | a heat treatment for pressure vessels subjected to low temperatures |
| E. | surface coating process |
| Answer» C. Increasing the diameter of threaded portion | |
| 316. |
Which of the following formula for columns takes into account any initial crookedness of the column and imperfectness of axial loading? |
| A. | Secant formula |
| B. | Increasing the diameter of threaded portion |
| C. | Euler's formula |
| D. | Rankiness formula |
| E. | Perry Robertson formula |
| Answer» B. Increasing the diameter of threaded portion | |
| 317. |
Self-tapping screws are generally used in |
| A. | Shear metal work |
| B. | Machine tools |
| C. | Automobiles |
| D. | Aeroplanes |
| E. | None of the above |
| Answer» B. Machine tools | |
| 318. |
In a standard coarse thread bolt the stress concentration is maximum at |
| A. | Top surface |
| B. | Pitch circle |
| C. | Root |
| D. | All over the surface |
| E. | Flank |
| Answer» D. All over the surface | |
| 319. |
If a machine member is loaded in such a way that the three principal stresses at a point are 600 kg/cm2 tension, 800 kg/cm2 compression and zero. The maximum shear stress at the point will be |
| A. | 400 kg/cm2 |
| B. | 800 kg/cm2 |
| C. | 600 kg/cm2 |
| D. | 1000 kg/cm2 |
| E. | 200 kg/cm2 |
| Answer» B. 800 kg/cm2 | |
| 320. |
In a Vee belt the angle between the sides is |
| A. | 30? |
| B. | 20? |
| C. | 60? |
| D. | 40? |
| E. | 10? |
| Answer» E. 10? | |
| 321. |
Wing screws are used where |
| A. | tight grip is essential |
| B. | frequently manual locking and unlocking is necessary |
| C. | stress reversal is severe |
| D. | high torque is needed for tightening |
| E. | Increasing the diameter of threaded portion |
| Answer» C. stress reversal is severe | |
| 322. |
Which of the following is not the result of cold work? |
| A. | Increased tensile strength |
| B. | Increasing the diameter of threaded portion |
| C. | Reduced ductility |
| D. | Reduced shock resistance |
| E. | Reduced hardness |
| Answer» F. | |
| 323. |
All of the following statements are false except |
| A. | The pitch of a sinle threaded screw is equal to the lead |
| B. | In a flange coupling, the bolts are subjected to compressive stress |
| C. | Oldham coupling is used for connecting piston rod of a steam engine to the cross head |
| D. | The resilience of a bolt may be increased by decreasing its shank diameter |
| E. | Increasing the diameter of threaded portion |
| Answer» B. In a flange coupling, the bolts are subjected to compressive stress | |
| 324. |
In V-belt drive the belt touches |
| A. | At bottom |
| B. | At sides only |
| C. | Both at bottom as well as sides |
| D. | Anywhere |
| E. | None of the above |
| Answer» F. | |
| 325. |
The basic design stress adopted for the design of light gauge steel members is |
| A. | the stress at limit of proportionality |
| B. | the yield stress divided by 1.85 |
| C. | the yied stress |
| D. | the permissible stress |
| E. | Increasing the diameter of threaded portion |
| Answer» C. the yied stress | |
| 326. |
In watches and gramophones, which spring is most commonly used |
| A. | Flat spiral spring |
| B. | torsion helical spring |
| C. | conical helical spring |
| D. | none of the above |
| E. | Cast steel |
| Answer» B. torsion helical spring | |
| 327. |
The edges of boiler plates for fullering and caulking are bevelled at an angle of |
| A. | 60? |
| B. | 45? |
| C. | 70? |
| D. | 30? |
| E. | 80? |
| Answer» F. | |
| 328. |
A taper bearing has |
| A. | Tapered roller |
| B. | Tapered inner race |
| C. | Tapered shaft |
| D. | Tapered cage |
| E. | Tapered outer race |
| Answer» B. Tapered inner race | |
| 329. |
Regenerative braking is used on |
| A. | Earth moving machines |
| B. | Heavy duty trucks |
| C. | Electric locomotives |
| D. | Diesel locomotives |
| E. | Steam locomotives |
| Answer» D. Diesel locomotives | |
| 330. |
While designing for screw threads care should be taken to provide adequate length of engagement for the screw and nut threads so as to prevent failure of threads in |
| A. | Tension |
| B. | Compression |
| C. | Torque |
| D. | Shear |
| E. | None of the above |
| Answer» E. None of the above | |
| 331. |
The plastic section modulus is |
| A. | the ratio of plastic moment capacity of a section to the yield moment |
| B. | Increasing the diameter of threaded portion |
| C. | the ratio of moment of inertia to radius of gyration |
| D. | the ratio of plastic moment capacity to the field stress |
| E. | area multiplied by the radius of gyration |
| Answer» B. Increasing the diameter of threaded portion | |
| 332. |
Stub teeth are provided on gears |
| A. | For high velocity ratios |
| B. | Low noise |
| C. | Large power transmission |
| D. | Improved capability to withstand shock and vibrations |
| E. | All of the above |
| Answer» E. All of the above | |
| 333. |
Ball bearing type screws |
| A. | Sliding friction is replaced by rolling friction |
| B. | There is a ball bearing provided on the screwed shafts |
| C. | Are self-locking |
| D. | Friction is more |
| E. | Have load bearing capacity for more than vee threads |
| Answer» B. There is a ball bearing provided on the screwed shafts | |
| 334. |
The piston of a internal combustion engine is subjected to |
| A. | fully reversed stresses |
| B. | repeated stresses |
| C. | Increasing the diameter of threaded portion |
| D. | partly repeated stresses |
| E. | partly reversed stresses |
| Answer» F. | |
| 335. |
In a central heating system, the seamless copper tubing used has an inside diameter of 20 mm and a wall thickness of 0.6 mm. For a maximum pressure of 1750 Kpa, when allowable stress is 225 Mpa, the safety factor will be |
| A. | 7.7 |
| B. | 9.9 |
| C. | 3.3 |
| D. | 5.5 |
| E. | Increasing the diameter of threaded portion |
| Answer» B. 9.9 | |
| 336. |
In a stone jaw crusher the main crank bearings are |
| A. | Taper roller bearings |
| B. | Roller bearings |
| C. | Ball bearings |
| D. | Double row ball bearings |
| E. | Self-aligning ball bearings |
| Answer» C. Ball bearings | |
| 337. |
The edge of the plates for boilers and tanks are usually bevelled at an angle of 80? |
| A. | To reduce stress concentration |
| B. | For safety |
| C. | To facilitate joining |
| D. | For fullering and caulking |
| E. | None of the above |
| Answer» E. None of the above | |
| 338. |
A self-socking screw is one which |
| A. | Has locking arrangement |
| B. | Has a hole drilled through for inserting locking pin |
| C. | Has coefficient of friction equal to or greater than the tangent of the load angle |
| D. | Has fine pitch screw threads |
| E. | None of the above |
| Answer» D. Has fine pitch screw threads | |
| 339. |
Lewis equation in ears is used to evaluate |
| A. | Tensile stress in bending |
| B. | Compressive stress in bending |
| C. | Creep stress |
| D. | Endurance limit |
| E. | Shear stress on flank |
| Answer» C. Creep stress | |
| 340. |
Maximum gear ratio can be expected in case of |
| A. | Spur gears |
| B. | Worm and worm wheel |
| C. | Helical gears |
| D. | Straight bevel gears |
| E. | Double helical gears |
| Answer» C. Helical gears | |
| 341. |
Neglecting bending, for a parallel load on a fillet weld of equal legs the plane of maximum shear occurs at |
| A. | 45? |
| B. | 15? |
| C. | 60? |
| D. | 30? |
| E. | 22 |
| Answer» B. 15? | |
| 342. |
Which pair of gears usually has high friction losses? |
| A. | All have equal frictional loss |
| B. | Spur gears |
| C. | Bevel gears |
| D. | Helical gears |
| E. | Worm and worm wheel |
| Answer» F. | |
| 343. |
In the case of ball bearings the contacting areas between balls and running tracks are |
| A. | circular |
| B. | parabolic |
| C. | elliptical |
| D. | none of the above |
| E. | Cast steel |
| Answer» D. none of the above | |
| 344. |
The value of yield stress for structural steel is about |
| A. | Increasing the diameter of threaded portion |
| B. | 3600 kg/cm2 |
| C. | 1600 kg/cm2 |
| D. | 4600 kg/cm2 |
| E. | 2600 kg/cm2 |
| Answer» F. | |
| 345. |
Poisson's ratio for rubber is taken as |
| A. | 0.1 |
| B. | 1 |
| C. | Zero |
| D. | 2 |
| E. | 0.5 |
| Answer» F. | |
| 346. |
The maximum size of the fillet weld that can be used is |
| A. | Increasing the diameter of threaded portion |
| B. | 3 mm |
| C. | 7 mm |
| D. | 1 mm |
| E. | 5 mm |
| Answer» C. 7 mm | |
| 347. |
In plastic analysis, the shape factor of a triangular section is |
| A. | 1.15 |
| B. | Increasing the diameter of threaded portion |
| C. | 2.34 |
| D. | 1.5 |
| E. | 1.85 |
| Answer» D. 1.5 | |
| 348. |
The diameter of rivets for 20 mm thick plates would be |
| A. | 10 mm |
| B. | 20 mm |
| C. | 15 mm |
| D. | 40 mm |
| E. | 30 mm |
| Answer» E. 30 mm | |
| 349. |
The plastic design of a structure based on which of the following is always safe? |
| A. | Mechanism method of analysis |
| B. | Statistical method of plastic analysis |
| C. | Upper bound theorem of plastic analysis |
| D. | All of the above |
| E. | Increasing the diameter of threaded portion |
| Answer» C. Upper bound theorem of plastic analysis | |
| 350. |
The plastic design of steel structures which is based on upper bound theorem is |
| A. | safe, unsafe |
| B. | Increasing the diameter of threaded portion |
| C. | unsafe, unsafe |
| D. | safe, safe |
| E. | unsafe, safe |
| Answer» F. | |